*{ ... } может уменьшить стабильность, в смысле, что количество вызовов движка регекспов в будущем изменится. *)

The use of (?{ ... }) and (??{ ... }) in a pattern disables various optimisations globally in that pattern. This may or may not be desired by the programmer. This release adds the (*{ ... }) equivalent. The only difference is that it does not and will never disable any optimisations in the regex engine.

*) This may make it more unstable in the sense that it may be called more or less times in the future, however the number of times it executes will truly match how the regex engine functions. For example, certain types of optimisation are disabled when (?{ ... }) is included in a pattern, so that patterns which are O(N) in normal use become O(N*N) with a (?{ ... }) pattern in them. Switching to (*{ ... }) means the pattern will stay O(N).